sql server 2005 - ALTER COLUMN query taking too much time -

i using microsoft sql server 2005. have table tbltest has column called displayvalue. current data type , length nvarchar(1000). trying change size of column using below query -

begin tran alter table [schema name].[tbltest] alter column displayvalue nvarchar(4000) -- commit -- rollback 

but when execute query going in process doesn't completed. have waited 40 minutes still in progress. have tried several times no luck. can please me.

there 2540 records in table. there no uncommited transaction.

i have tried same query in machine. it's working fine me.

restart sql server services , execute code. or try change through query design using ssms tool.